The invention relates to a method for providing the subscriber number of the calling subscriber in connection requests routed from a private communications network (PRNET) into a public communications network (PUBNET) a service unit for supporting the provision of the subscriber number of the calling subscriber in connection requests and a private communications network incorporating such a service unit.
The invention is based on the facility xe2x80x9cTransmission of Subscriber Number of Calling Subscriberxe2x80x9d provided in an ISDN communications system (ISDN=Integrated Services Digital Network), described for example in DE OS 41 01 885 A1.
In the connection request routed through the ISDN communications system for the establishment of a connection in the direction of the called subscriber, the subscriber number of the calling subscriber is transported by the ISDN communications system to the terminal of the called subscriber, where the subscriber number of the calling subscriber is then displayed to the called subscriber or this information is used as input information for CSTA applications (CSTA=Computer Supported Telecommunication Application). This information can also serve as the basis for a call-back of the called subscriber.
It is therefore of particular importance that this information is correctly transmitted to the terminal of the called subscriber. However, this is not always the case if the calling subscriber is associated with a private communications network.
The object of the invention is to improve the quality of the transmission of the subscriber number of the calling subscriber in a connection request in the event that the calling subscriber is connected via a private communications network to the public communications network.
This object is achieved by a method for providing the subscriber number of the calling subscriber in connection requests, a service unit for supporting the provision of the subscriber number of the calling subscriber in connection requests, and a private communications network including such a service unit, all as described below.
The invention is based on the concept that the subscriber number of the calling subscriber is not correctly provided in the connection request if the connection request is routed from the private communications network into the public communications network in a local network area which does not correspond to the local network area assigned to the calling subscriber. A service unit of the public communications network detects such a connection request and ensures that the correct subscriber number of the calling subscriber is entered in the connection request.
The advantage of the invention is that ISDN and CSTA facilities based on information about the calling subscriber also function correctly for subscribers of private communications networks. This service can also easily be offered by a public communications network operator to large customers as an additional service.
Advantageous developments of the invention are described in the sub-claims.